What’s to be said? Except that C. S. Lewis is a better storyteller than the folks at Walden. They can’t just trust a classic–they need to add unnecessary people and plot devices and take out details that are important to Lewis.
In this movie, they can’t have a simple quest–it needs to be turned into a search for magic swords. Eustace saves the day by fighting the sea monster in the mist of the dark island (there’s a pile up of plot knots!), and then takes the last magic sword to the table–then, suddenly, after de-dragoning by Aslan, he’s in the water by the ship.
Having the swords, the sleepers at the table awake. There’s no need for someone to sail to the end of the earth. But it’s close, so let’s do it anyway! Caspian doesn’t get rebuffed by Aslan till after he goes to the end of the world in the row boat (meaning he has to row back to the Dawn Treader by himself–but where’d the ship go?). Reep’s coracle suddenly appears on the beach–where was it before? Gone is the scene of the lamb frying fish on the beach–critical Christological imagery.
Read the book for Lewis. Watch the BBC version for a faithful adaptation. Watch this if you just crave special effects.